Effective utilization of fibrous materials plays a major role in techno-economic viability of the resources. Sunflower stalk (SS) as one of highest bio-fibrous waste was assessed respect to fiber features in biorefinery approach. The lumen diameter, wall thickness and fiber length were measured as (∼12 µm), (5.25 µm) and (1.58 mm), respectively. The wider lumen diameter makes its suitable for chemical treatments and purification. The applied Pulping conditions decreased the fiber length and wall thickness, with the least reduction by soda-anthraquinone. Derived indices involved rigidity and flexibility coefficients, aspect and Runkel ratios, solid and Luce’s shape factors were also calculated based on the measured values. The aspect ratio (77.5) put SS fibers as very good resources for lignocellulosic products and composites. The flexibility coefficient (57) belongs to the elastic category and was not altered by pulping. The Runkel ratio was lesser than 1 (>0.9) but decreased by the pulping, to some extent. The Luceʼs shape factor was nearly calculated 0.5, near to the bagasse and eucalyptus species. Solid factor (0.17) and rigidity coefficient (0.51) were considered to be good fiber resource. Totally due to the SS fiber characteristics, the agricultural waste suitability for value adding bio-based production could be reported.